summaryrefslogtreecommitdiffstats
path: root/fs/ocfs2/extent_map.c
blob: e6f207eebab422031860c4ef13fed84d351acee7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * extent_map.c
 *
 * In-memory extent map for OCFS2.  Man, this code was prettier in
 * the library.
 *
 * Copyright (C) 2004 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License, version 2,  as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#include <linux/fs.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/rbtree.h>

#define MLOG_MASK_PREFIX ML_EXTENT_MAP
#include <cluster/masklog.h>

#include "ocfs2.h"

#include "extent_map.h"
#include "inode.h"
#include "super.h"

#include "buffer_head_io.h"


/*
 * SUCK SUCK SUCK
 * Our headers are so bad that struct ocfs2_extent_map is in ocfs.h
 */

struct ocfs2_extent_map_entry {
	struct rb_node e_node;
	int e_tree_depth;
	struct ocfs2_extent_rec e_rec;
};

struct ocfs2_em_insert_context {
	int need_left;
	int need_right;
	struct ocfs2_extent_map_entry *new_ent;
	struct ocfs2_extent_map_entry *old_ent;
	struct ocfs2_extent_map_entry *left_ent;
	struct ocfs2_extent_map_entry *right_ent;
};

static kmem_cache_t *ocfs2_em_ent_cachep = NULL;


static struct ocfs2_extent_map_entry *
ocfs2_extent_map_lookup(struct ocfs2_extent_map *em,
			u32 cpos, u32 clusters,
			struct rb_node ***ret_p,
			struct rb_node **ret_parent);
static int ocfs2_extent_map_insert(struct inode *inode,
				   struct ocfs2_extent_rec *rec,
				   int tree_depth);
static int ocfs2_extent_map_insert_entry(struct ocfs2_extent_map *em,
					 struct ocfs2_extent_map_entry *ent);
static int ocfs2_extent_map_find_leaf(struct inode *inode,
				      u32 cpos, u32 clusters,
				      struct ocfs2_extent_list *el);
static int ocfs2_extent_map_lookup_read(struct inode *inode,
					u32 cpos, u32 clusters,
					struct ocfs2_extent_map_entry **ret_ent);
static int ocfs2_extent_map_try_insert(struct inode *inode,
				       struct ocfs2_extent_rec *rec,
				       int tree_depth,
				       struct ocfs2_em_insert_context *ctxt);

/* returns 1 only if the rec contains all the given clusters -- that is that
 * rec's cpos is <= the cluster cpos and that the rec endpoint (cpos +
 * clusters) is >= the argument's endpoint */
static int ocfs2_extent_rec_contains_clusters(struct ocfs2_extent_rec *rec,
					      u32 cpos, u32 clusters)
{
	if (le32_to_cpu(rec->e_cpos) > cpos)
		return 0;
	if (cpos + clusters > le32_to_cpu(rec->e_cpos) + 
			      le32_to_cpu(rec->e_clusters))
		return 0;
	return 1;
}


/*
 * Find an entry in the tree that intersects the region passed in.
 * Note that this will find straddled intervals, it is up to the
 * callers to enforce any boundary conditions.
 *
 * Callers must hold ip_lock.  This lookup is not guaranteed to return
 * a tree_depth 0 match, and as such can race inserts if the lock
 * were not held.
 *
 * The rb_node garbage lets insertion share the search.  Trivial
 * callers pass NULL.
 */
static struct ocfs2_extent_map_entry *
ocfs2_extent_map_lookup(struct ocfs2_extent_map *em,
			u32 cpos, u32 clusters,
			struct rb_node ***ret_p,
			struct rb_node **ret_parent)
{
	struct rb_node **p = &em->em_extents.rb_node;
	struct rb_node *parent = NULL;
	struct ocfs2_extent_map_entry *ent = NULL;

	while (*p)
	{
		parent = *p;
		ent = rb_entry(parent, struct ocfs2_extent_map_entry,
			       e_node);
		if ((cpos + clusters) <= le32_to_cpu(ent->e_rec.e_cpos)) {
			p = &(*p)->rb_left;
			ent = NULL;
		} else if (cpos >= (le32_to_cpu(ent->e_rec.e_cpos) +
				    le32_to_cpu(ent->e_rec.e_clusters))) {
			p = &(*p)->rb_right;
			ent = NULL;
		} else
			break;
	}

	if (ret_p != NULL)
		*ret_p = p;
	if (ret_parent != NULL)
		*ret_parent = parent;
	return ent;
}

/*
 * Find the leaf containing the interval we want.  While we're on our
 * way down the tree, fill in every record we see at any depth, because
 * we might want it later.
 *
 * Note that this code is run without ip_lock.  That's because it
 * sleeps while reading.  If someone is also filling the extent list at
 * the same time we are, we might have to restart.
 */
static int ocfs2_extent_map_find_leaf(struct inode *inode,
				      u32 cpos, u32 clusters,
				      struct ocfs2_extent_list *el)
{
	int i, ret;
	struct buffer_head *eb_bh = NULL;
	u64 blkno;
	u32 rec_end;
	struct ocfs2_extent_block *eb;
	struct ocfs2_extent_rec *rec;

	/*
	 * The bh data containing the el cannot change here, because
	 * we hold alloc_sem.  So we can do this without other
	 * locks.
	 */
	while (el->l_tree_depth)
	{
		blkno = 0;
		for (i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
			rec = &el->l_recs[i];
			rec_end = (le32_to_cpu(rec->e_cpos) +
				   le32_to_cpu(rec->e_clusters));

			ret = -EBADR;
			if (rec_end > OCFS2_I(inode)->ip_clusters) {
				mlog_errno(ret);
				ocfs2_error(inode->i_sb,
					    "Extent %d at e_blkno %"MLFu64" of inode %"MLFu64" goes past ip_clusters of %u\n",
					    i,
					    le64_to_cpu(rec->e_blkno),
					    OCFS2_I(inode)->ip_blkno,
					    OCFS2_I(inode)->ip_clusters);
				goto out_free;
			}

			if (rec_end <= cpos) {
				ret = ocfs2_extent_map_insert(inode, rec,
						le16_to_cpu(el->l_tree_depth));
				if (ret && (ret != -EEXIST)) {
					mlog_errno(ret);
					goto out_free;
				}
				continue;
			}
			if ((cpos + clusters) <= le32_to_cpu(rec->e_cpos)) {
				ret = ocfs2_extent_map_insert(inode, rec,
						le16_to_cpu(el->l_tree_depth));
				if (ret && (ret != -EEXIST)) {
					mlog_errno(ret);
					goto out_free;
				}
				continue;
			}

			/*
			 * We've found a record that matches our
			 * interval.  We don't insert it because we're
			 * about to traverse it.
			 */

			/* Check to see if we're stradling */
			ret = -ESRCH;
			if (!ocfs2_extent_rec_contains_clusters(rec,
							        cpos,
								clusters)) {
				mlog_errno(ret);
				goto out_free;
			}

			/*
			 * If we've already found a record, the el has
			 * two records covering the same interval.
			 * EEEK!
			 */
			ret = -EBADR;
			if (blkno) {
				mlog_errno(ret);
				ocfs2_error(inode->i_sb,
					    "Multiple extents for (cpos = %u, clusters = %u) on inode %"MLFu64"; e_blkno %"MLFu64" and rec %d at e_blkno %"MLFu64"\n",
					    cpos, clusters,
					    OCFS2_I(inode)->ip_blkno,
					    blkno, i,
					    le64_to_cpu(rec->e_blkno));
				goto out_free;
			}

			blkno = le64_to_cpu(rec->e_blkno);
		}

		/*
		 * We don't support holes, and we're still up
		 * in the branches, so we'd better have found someone
		 */
		ret = -EBADR;
		if (!blkno) {
			ocfs2_error(inode->i_sb,
				    "No record found for (cpos = %u, clusters = %u) on inode %"MLFu64"\n",
				    cpos, clusters,
				    OCFS2_I(inode)->ip_blkno);
			mlog_errno(ret);
			goto out_free;
		}

		if (eb_bh) {
			brelse(eb_bh);
			eb_bh = NULL;
		}
		ret = ocfs2_read_block(OCFS2_SB(inode->i_sb),
				       blkno, &eb_bh, OCFS2_BH_CACHED,
				       inode);
		if (ret) {
			mlog_errno(ret);
			goto out_free;
		}
		eb = (struct ocfs2_extent_block *)eb_bh->b_data;
		if (!OCFS2_IS_VALID_EXTENT_BLOCK(eb)) {
			OCFS2_RO_ON_INVALID_EXTENT_BLOCK(inode->i_sb, eb);
			ret = -EIO;
			goto out_free;
		}
		el = &eb->h_list;
	}

	BUG_ON(el->l_tree_depth);

	for (i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
		rec = &el->l_recs[i];

		if ((le32_to_cpu(rec->e_cpos) + le32_to_cpu(rec->e_clusters)) >
		    OCFS2_I(inode)->ip_clusters) {
			ret = -EBADR;
			mlog_errno(ret);
			ocfs2_error(inode->i_sb,
				    "Extent %d at e_blkno %"MLFu64" of inode %"MLFu64" goes past ip_clusters of %u\n",
				    i,
				    le64_to_cpu(rec->e_blkno),
				    OCFS2_I(inode)->ip_blkno,
				    OCFS2_I(inode)->ip_clusters);
			return ret;
		}

		ret = ocfs2_extent_map_insert(inode, rec,
					      le16_to_cpu(el->l_tree_depth));
		if (ret) {
			mlog_errno(ret);
			goto out_free;
		}
	}

	ret = 0;

out_free:
	if (eb_bh)
		brelse(eb_bh);

	return ret;
}

/*
 * This lookup actually will read from disk.  It has one invariant:
 * It will never re-traverse blocks.  This means that all inserts should
 * be new regions or more granular regions (both allowed by insert).
 */
static int ocfs2_extent_map_lookup_read(struct inode *inode,
					u32 cpos,
					u32 clusters,
					struct ocfs2_extent_map_entry **ret_ent)
{
	int ret;
	u64 blkno;
	struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
	struct ocfs2_extent_map_entry *ent;
	struct buffer_head *bh = NULL;
	struct ocfs2_extent_block *eb;
	struct ocfs2_dinode *di;
	struct ocfs2_extent_list *el;

	spin_lock(&OCFS2_I(inode)->ip_lock);
	ent = ocfs2_extent_map_lookup(em, cpos, clusters, NULL, NULL);
	if (ent) {
		if (!ent->e_tree_depth) {
			spin_unlock(&OCFS2_I(inode)->ip_lock);
			*ret_ent = ent;
			return 0;
		}
		blkno = le64_to_cpu(ent->e_rec.e_blkno);
		spin_unlock(&OCFS2_I(inode)->ip_lock);

		ret = ocfs2_read_block(OCFS2_SB(inode->i_sb), blkno, &bh,
				       OCFS2_BH_CACHED, inode);
		if (ret) {
			mlog_errno(ret);
			if (bh)
				brelse(bh);
			return ret;
		}
		eb = (struct ocfs2_extent_block *)bh->b_data;
		if (!OCFS2_IS_VALID_EXTENT_BLOCK(eb)) {
			OCFS2_RO_ON_INVALID_EXTENT_BLOCK(inode->i_sb, eb);
			brelse(bh);
			return -EIO;
		}
		el = &eb->h_list;
	} else {
		spin_unlock(&OCFS2_I(inode)->ip_lock);

		ret = ocfs2_read_block(OCFS2_SB(inode->i_sb),
				       OCFS2_I(inode)->ip_blkno, &bh,
				       OCFS2_BH_CACHED, inode);
		if (ret) {
			mlog_errno(ret);
			if (bh)
				brelse(bh);
			return ret;
		}
		di = (struct ocfs2_dinode *)bh->b_data;
		if (!OCFS2_IS_VALID_DINODE(di)) {
			brelse(bh);
			OCFS2_RO_ON_INVALID_DINODE(inode->i_sb, di);
			return -EIO;
		}
		el = &di->id2.i_list;
	}

	ret = ocfs2_extent_map_find_leaf(inode, cpos, clusters, el);
	brelse(bh);
	if (ret) {
		mlog_errno(ret);
		return ret;
	}

	ent = ocfs2_extent_map_lookup(em, cpos, clusters, NULL, NULL);
	if (!ent) {
		ret = -ESRCH;
		mlog_errno(ret);
		return ret;
	}

	/* FIXME: Make sure this isn't a corruption */
	BUG_ON(ent->e_tree_depth);

	*ret_ent = ent;

	return 0;
}

/*
 * Callers must hold ip_lock.  This can insert pieces of the tree,
 * thus racing lookup if the lock weren't held.
 */
static int ocfs2_extent_map_insert_entry(struct ocfs2_extent_map *em,
					 struct ocfs2_extent_map_entry *ent)
{
	struct rb_node **p, *parent;
	struct ocfs2_extent_map_entry *old_ent;

	old_ent = ocfs2_extent_map_lookup(em, le32_to_cpu(ent->e_rec.e_cpos),
					  le32_to_cpu(ent->e_rec.e_clusters),
					  &p, &parent);
	if (old_ent)
		return -EEXIST;

	rb_link_node(&ent->e_node, parent, p);
	rb_insert_color(&ent->e_node, &em->em_extents);

	return 0;
}


/*
 * Simple rule: on any return code other than -EAGAIN, anything left
 * in the insert_context will be freed.
 */
static int ocfs2_extent_map_try_insert(struct inode *inode,
				       struct ocfs2_extent_rec *rec,
				       int tree_depth,
				       struct ocfs2_em_insert_context *ctxt)
{
	int ret;
	struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
	struct ocfs2_extent_map_entry *old_ent;

	ctxt->need_left = 0;
	ctxt->need_right = 0;
	ctxt->old_ent = NULL;

	spin_lock(&OCFS2_I(inode)->ip_lock);
	ret = ocfs2_extent_map_insert_entry(em, ctxt->new_ent);
	if (!ret) {
		ctxt->new_ent = NULL;
		goto out_unlock;
	}

	old_ent = ocfs2_extent_map_lookup(em, le32_to_cpu(rec->e_cpos),
					  le32_to_cpu(rec->e_clusters), NULL,
					  NULL);

	BUG_ON(!old_ent);

	ret = -EEXIST;
	if (old_ent->e_tree_depth < tree_depth)
		goto out_unlock;

	if (old_ent->e_tree_depth == tree_depth) {
		if (!memcmp(rec, &old_ent->e_rec,
			    sizeof(struct ocfs2_extent_rec)))
			ret = 0;

		/* FIXME: Should this be ESRCH/EBADR??? */
		goto out_unlock;
	}

	/*
	 * We do it in this order specifically so that no actual tree
	 * changes occur until we have all the pieces we need.  We
	 * don't want malloc failures to leave an inconsistent tree.
	 * Whenever we drop the lock, another process could be
	 * inserting.  Also note that, if another process just beat us
	 * to an insert, we might not need the same pieces we needed
	 * the first go round.  In the end, the pieces we need will
	 * be used, and the pieces we don't will be freed.
	 */
	ctxt->need_left = !!(le32_to_cpu(rec->e_cpos) >
			     le32_to_cpu(old_ent->e_rec.e_cpos));
	ctxt->need_right = !!((le32_to_cpu(old_ent->e_rec.e_cpos) +
			       le32_to_cpu(old_ent->e_rec.e_clusters)) >
			      (le32_to_cpu(rec->e_cpos) + le32_to_cpu(rec->e_clusters)));
	ret = -EAGAIN;
	if (ctxt->need_left) {
		if (!ctxt->left_ent)
			goto out_unlock;
		*(ctxt->left_ent) = *old_ent;
		ctxt->left_ent->e_rec.e_clusters =
			cpu_to_le32(le32_to_cpu(rec->e_cpos) -
				    le32_to_cpu(ctxt->left_ent->e_rec.e_cpos));
	}
	if (ctxt->need_right) {
		if (!ctxt->right_ent)
			goto out_unlock;
		*(ctxt->right_ent) = *old_ent;
		ctxt->right_ent->e_rec.e_cpos =
			cpu_to_le32(le32_to_cpu(rec->e_cpos) +
				    le32_to_cpu(rec->e_clusters));
		ctxt->right_ent->e_rec.e_clusters =
			cpu_to_le32((le32_to_cpu(old_ent->e_rec.e_cpos) +
				     le32_to_cpu(old_ent->e_rec.e_clusters)) -
				    le32_to_cpu(ctxt->right_ent->e_rec.e_cpos));
	}

	rb_erase(&old_ent->e_node, &em->em_extents);
	/* Now that he's erased, set him up for deletion */
	ctxt->old_ent = old_ent;

	if (ctxt->need_left) {
		ret = ocfs2_extent_map_insert_entry(em,
						    ctxt->left_ent);
		if (ret)
			goto out_unlock;
		ctxt->left_ent = NULL;
	}

	if (ctxt->need_right) {
		ret = ocfs2_extent_map_insert_entry(em,
						    ctxt->right_ent);
		if (ret)
			goto out_unlock;
		ctxt->right_ent = NULL;
	}

	ret = ocfs2_extent_map_insert_entry(em, ctxt->new_ent);

	if (!ret)
		ctxt->new_ent = NULL;

out_unlock:
	spin_unlock(&OCFS2_I(inode)->ip_lock);

	return ret;
}


static int ocfs2_extent_map_insert(struct inode *inode,
				   struct ocfs2_extent_rec *rec,
				   int tree_depth)
{
	int ret;
	struct ocfs2_em_insert_context ctxt = {0, };

	if ((le32_to_cpu(rec->e_cpos) + le32_to_cpu(rec->e_clusters)) >
	    OCFS2_I(inode)->ip_map.em_clusters) {
		ret = -EBADR;
		mlog_errno(ret);
		return ret;
	}

	/* Zero e_clusters means a truncated tail record.  It better be EOF */
	if (!rec->e_clusters) {
		if ((le32_to_cpu(rec->e_cpos) + le32_to_cpu(rec->e_clusters)) !=
		    OCFS2_I(inode)->ip_map.em_clusters) {
			ret = -EBADR;
			mlog_errno(ret);
			ocfs2_error(inode->i_sb,
				    "Zero e_clusters on non-tail extent record at e_blkno %"MLFu64" on inode %"MLFu64"\n",
				    le64_to_cpu(rec->e_blkno),
				    OCFS2_I(inode)->ip_blkno);
			return ret;
		}

		/* Ignore the truncated tail */
		return 0;
	}

	ret = -ENOMEM;
	ctxt.new_ent = kmem_cache_alloc(ocfs2_em_ent_cachep,
					GFP_KERNEL);
	if (!ctxt.new_ent) {
		mlog_errno(ret);
		return ret;
	}

	ctxt.new_ent->e_rec = *rec;
	ctxt.new_ent->e_tree_depth = tree_depth;

	do {
		ret = -ENOMEM;
		if (ctxt.need_left && !ctxt.left_ent) {
			ctxt.left_ent =
				kmem_cache_alloc(ocfs2_em_ent_cachep,
						 GFP_KERNEL);
			if (!ctxt.left_ent)
				break;
		}
		if (ctxt.need_right && !ctxt.right_ent) {
			ctxt.right_ent =
				kmem_cache_alloc(ocfs2_em_ent_cachep,
						 GFP_KERNEL);
			if (!ctxt.right_ent)
				break;
		}

		ret = ocfs2_extent_map_try_insert(inode, rec,
						  tree_depth, &ctxt);
	} while (ret == -EAGAIN);

	if (ret < 0)
		mlog_errno(ret);

	if (ctxt.left_ent)
		kmem_cache_free(ocfs2_em_ent_cachep, ctxt.left_ent);
	if (ctxt.right_ent)
		kmem_cache_free(ocfs2_em_ent_cachep, ctxt.right_ent);
	if (ctxt.old_ent)
		kmem_cache_free(ocfs2_em_ent_cachep, ctxt.old_ent);
	if (ctxt.new_ent)
		kmem_cache_free(ocfs2_em_ent_cachep, ctxt.new_ent);

	return ret;
}

/*
 * Append this record to the tail of the extent map.  It must be
 * tree_depth 0.  The record might be an extension of an existing
 * record, and as such that needs to be handled.  eg:
 *
 * Existing record in the extent map:
 *
 *	cpos = 10, len = 10
 *	|---------|
 *
 * New Record:
 *
 *	cpos = 10, len = 20
 *	|------------------|
 *
 * The passed record is the new on-disk record.  The new_clusters value
 * is how many clusters were added to the file.  If the append is a
 * contiguous append, the new_clusters has been added to
 * rec->e_clusters.  If the append is an entirely new extent, then
 * rec->e_clusters is == new_clusters.
 */
int ocfs2_extent_map_append(struct inode *inode,
			    struct ocfs2_extent_rec *rec,
			    u32 new_clusters)
{
	int ret;
	struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
	struct ocfs2_extent_map_entry *ent;
	struct ocfs2_extent_rec *old;

	BUG_ON(!new_clusters);
	BUG_ON(le32_to_cpu(rec->e_clusters) < new_clusters);

	if (em->em_clusters < OCFS2_I(inode)->ip_clusters) {
		/*
		 * Size changed underneath us on disk.  Drop any
		 * straddling records and update our idea of
		 * i_clusters
		 */
		ocfs2_extent_map_drop(inode, em->em_clusters - 1);
		em->em_clusters = OCFS2_I(inode)->ip_clusters;
	}

	mlog_bug_on_msg((le32_to_cpu(rec->e_cpos) +
			 le32_to_cpu(rec->e_clusters)) !=
			(em->em_clusters + new_clusters),
			"Inode %"MLFu64":\n"
			"rec->e_cpos = %u + rec->e_clusters = %u = %u\n"
			"em->em_clusters = %u + new_clusters = %u = %u\n",
			OCFS2_I(inode)->ip_blkno,
			le32_to_cpu(rec->e_cpos), le32_to_cpu(rec->e_clusters),
			le32_to_cpu(rec->e_cpos) + le32_to_cpu(rec->e_clusters),
			em->em_clusters, new_clusters,
			em->em_clusters + new_clusters);

	em->em_clusters += new_clusters;

	ret = -ENOENT;
	if (le32_to_cpu(rec->e_clusters) > new_clusters) {
		/* This is a contiguous append */
		ent = ocfs2_extent_map_lookup(em, le32_to_cpu(rec->e_cpos), 1,
					      NULL, NULL);
		if (ent) {
			old = &ent->e_rec;
			BUG_ON((le32_to_cpu(rec->e_cpos) +
				le32_to_cpu(rec->e_clusters)) !=
				 (le32_to_cpu(old->e_cpos) +
				  le32_to_cpu(old->e_clusters) +
				  new_clusters));
			if (ent->e_tree_depth == 0) {
				BUG_ON(le32_to_cpu(old->e_cpos) !=
				       le32_to_cpu(rec->e_cpos));
				BUG_ON(le64_to_cpu(old->e_blkno) !=
				       le64_to_cpu(rec->e_blkno));
				ret = 0;
			}
			/*
			 * Let non-leafs fall through as -ENOENT to
			 * force insertion of the new leaf.
			 */
			le32_add_cpu(&old->e_clusters, new_clusters);
		}
	}

	if (ret == -ENOENT)
		ret = ocfs2_extent_map_insert(inode, rec, 0);
	if (ret < 0)
		mlog_errno(ret);
	return ret;
}

#if 0
/* Code here is included but defined out as it completes the extent
 * map api and may be used in the future. */

/*
 * Look up the record containing this cluster offset.  This record is
 * part of the extent map.  Do not free it.  Any changes you make to
 * it will reflect in the extent map.  So, if your last extent
 * is (cpos = 10, clusters = 10) and you truncate the file by 5
 * clusters, you can do:
 *
 * ret = ocfs2_extent_map_get_rec(em, orig_size - 5, &rec);
 * rec->e_clusters -= 5;
 *
 * The lookup does not read from disk.  If the map isn't filled in for
 * an entry, you won't find it.
 *
 * Also note that the returned record is valid until alloc_sem is
 * dropped.  After that, truncate and extend can happen.  Caveat Emptor.
 */
int ocfs2_extent_map_get_rec(struct inode *inode, u32 cpos,
			     struct ocfs2_extent_rec **rec,
			     int *tree_depth)
{
	int ret = -ENOENT;
	struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
	struct ocfs2_extent_map_entry *ent;

	*rec = NULL;

	if (cpos >= OCFS2_I(inode)->ip_clusters)
		return -EINVAL;

	if (cpos >= em->em_clusters) {
		/*
		 * Size changed underneath us on disk.  Drop any
		 * straddling records and update our idea of
		 * i_clusters
		 */
		ocfs2_extent_map_drop(inode, em->em_clusters - 1);
		em->em_clusters = OCFS2_I(inode)->ip_clusters ;
	}

	ent = ocfs2_extent_map_lookup(&OCFS2_I(inode)->ip_map, cpos, 1,
				      NULL, NULL);

	if (ent) {
		*rec = &ent->e_rec;
		if (tree_depth)
			*tree_depth = ent->e_tree_depth;
		ret = 0;
	}

	return ret;
}

int ocfs2_extent_map_get_clusters(struct inode *inode,
				  u32 v_cpos, int count,
				  u32 *p_cpos, int *ret_count)
{
	int ret;
	u32 coff, ccount;
	struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
	struct ocfs2_extent_map_entry *ent = NULL;

	*p_cpos = ccount = 0;

	if ((v_cpos + count) > OCFS2_I(inode)->ip_clusters)
		return -EINVAL;

	if ((v_cpos + count) > em->em_clusters) {
		/*
		 * Size changed underneath us on disk.  Drop any
		 * straddling records and update our idea of
		 * i_clusters
		 */
		ocfs2_extent_map_drop(inode, em->em_clusters - 1);
		em->em_clusters = OCFS2_I(inode)->ip_clusters;
	}


	ret = ocfs2_extent_map_lookup_read(inode, v_cpos, count, &ent);
	if (ret)
		return ret;

	if (ent) {
		/* We should never find ourselves straddling an interval */
		if (!ocfs2_extent_rec_contains_clusters(&ent->e_rec,
							v_cpos,
							count))
			return -ESRCH;

		coff = v_cpos - le32_to_cpu(ent->e_rec.e_cpos);
		*p_cpos = ocfs2_blocks_to_clusters(inode->i_sb,
				le64_to_cpu(ent->e_rec.e_blkno)) +
			  coff;

		if (ret_count)
			*ret_count = le32_to_cpu(ent->e_rec.e_clusters) - coff;

		return 0;
	}


	return -ENOENT;
}

#endif  /*  0  */

int ocfs2_extent_map_get_blocks(struct inode *inode,
				u64 v_blkno, int count,
				u64 *p_blkno, int *ret_count)
{
	int ret;
	u64 boff;
	u32 cpos, clusters;
	int bpc = ocfs2_clusters_to_blocks(inode->i_sb, 1);
	struct ocfs2_extent_map_entry *ent = NULL;
	struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
	struct ocfs2_extent_rec *rec;

	*p_blkno = 0;

	cpos = ocfs2_blocks_to_clusters(inode->i_sb, v_blkno);
	clusters = ocfs2_blocks_to_clusters(inode->i_sb,
					    (u64)count + bpc - 1);
	if ((cpos + clusters) > OCFS2_I(inode)->ip_clusters) {
		ret = -EINVAL;
		mlog_errno(ret);
		return ret;
	}

	if ((cpos + clusters) > em->em_clusters) {
		/*
		 * Size changed underneath us on disk.  Drop any
		 * straddling records and update our idea of
		 * i_clusters
		 */
		ocfs2_extent_map_drop(inode, em->em_clusters - 1);
		em->em_clusters = OCFS2_I(inode)->ip_clusters;
	}

	ret = ocfs2_extent_map_lookup_read(inode, cpos, clusters, &ent);
	if (ret) {
		mlog_errno(ret);
		return ret;
	}

	if (ent)
	{
		rec = &ent->e_rec;

		/* We should never find ourselves straddling an interval */
		if (!ocfs2_extent_rec_contains_clusters(rec, cpos, clusters)) {
			ret = -ESRCH;
			mlog_errno(ret);
			return ret;
		}

		boff = ocfs2_clusters_to_blocks(inode->i_sb, cpos -
						le32_to_cpu(rec->e_cpos));
		boff += (v_blkno & (u64)(bpc - 1));
		*p_blkno = le64_to_cpu(rec->e_blkno) + boff;

		if (ret_count) {
			*ret_count = ocfs2_clusters_to_blocks(inode->i_sb,
					le32_to_cpu(rec->e_clusters)) - boff;
		}

		return 0;
	}

	return -ENOENT;
}

int ocfs2_extent_map_init(struct inode *inode)
{
	struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;

	em->em_extents = RB_ROOT;
	em->em_clusters = 0;

	return 0;
}

/* Needs the lock */
static void __ocfs2_extent_map_drop(struct inode *inode,
				    u32 new_clusters,
				    struct rb_node **free_head,
				    struct ocfs2_extent_map_entry **tail_ent)
{
	struct rb_node *node, *next;
	struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
	struct ocfs2_extent_map_entry *ent;

	*free_head = NULL;

	ent = NULL;
	node = rb_last(&em->em_extents);
	while (node)
	{
		next = rb_prev(node);

		ent = rb_entry(node, struct ocfs2_extent_map_entry,
			       e_node);
		if (le32_to_cpu(ent->e_rec.e_cpos) < new_clusters)
			break;

		rb_erase(&ent->e_node, &em->em_extents);

		node->rb_right = *free_head;
		*free_head = node;

		ent = NULL;
		node = next;
	}

	/* Do we have an entry straddling new_clusters? */
	if (tail_ent) {
		if (ent &&
		    ((le32_to_cpu(ent->e_rec.e_cpos) +
		      le32_to_cpu(ent->e_rec.e_clusters)) > new_clusters))
			*tail_ent = ent;
		else
			*tail_ent = NULL;
	}
}

static void __ocfs2_extent_map_drop_cleanup(struct rb_node *free_head)
{
	struct rb_node *node;
	struct ocfs2_extent_map_entry *ent;

	while (free_head) {
		node = free_head;
		free_head = node->rb_right;

		ent = rb_entry(node, struct ocfs2_extent_map_entry,
			       e_node);
		kmem_cache_free(ocfs2_em_ent_cachep, ent);
	}
}

/*
 * Remove all entries past new_clusters, inclusive of an entry that
 * contains new_clusters.  This is effectively a cache forget.
 *
 * If you want to also clip the last extent by some number of clusters,
 * you need to call ocfs2_extent_map_trunc().
 * This code does not check or modify ip_clusters.
 */
int ocfs2_extent_map_drop(struct inode *inode, u32 new_clusters)
{
	struct rb_node *free_head = NULL;
	struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
	struct ocfs2_extent_map_entry *ent;

	spin_lock(&OCFS2_I(inode)->ip_lock);

	__ocfs2_extent_map_drop(inode, new_clusters, &free_head, &ent);

	if (ent) {
		rb_erase(&ent->e_node, &em->em_extents);
		ent->e_node.rb_right = free_head;
		free_head = &ent->e_node;
	}

	spin_unlock(&OCFS2_I(inode)->ip_lock);

	if (free_head)
		__ocfs2_extent_map_drop_cleanup(free_head);

	return 0;
}

/*
 * Remove all entries past new_clusters and also clip any extent
 * straddling new_clusters, if there is one.  This does not check
 * or modify ip_clusters
 */
int ocfs2_extent_map_trunc(struct inode *inode, u32 new_clusters)
{
	struct rb_node *free_head = NULL;
	struct ocfs2_extent_map_entry *ent = NULL;

	spin_lock(&OCFS2_I(inode)->ip_lock);

	__ocfs2_extent_map_drop(inode, new_clusters, &free_head, &ent);

	if (ent)
		ent->e_rec.e_clusters = cpu_to_le32(new_clusters -
					       le32_to_cpu(ent->e_rec.e_cpos));

	OCFS2_I(inode)->ip_map.em_clusters = new_clusters;

	spin_unlock(&OCFS2_I(inode)->ip_lock);

	if (free_head)
		__ocfs2_extent_map_drop_cleanup(free_head);

	return 0;
}

int __init init_ocfs2_extent_maps(void)
{
	ocfs2_em_ent_cachep =
		kmem_cache_create("ocfs2_em_ent",
				  sizeof(struct ocfs2_extent_map_entry),
				  0, SLAB_HWCACHE_ALIGN, NULL, NULL);
	if (!ocfs2_em_ent_cachep)
		return -ENOMEM;

	return 0;
}

void exit_ocfs2_extent_maps(void)
{
	kmem_cache_destroy(ocfs2_em_ent_cachep);
}
OpenPOWER on IntegriCloud